package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.LOCK_ORDER_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author zys
 * 
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    //基于redis实现的分布式工具集合
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT =new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(long.class);
    }


    //创建线程池,进行异步下单
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在这个类初始化，就要执行该任务，进行异步下单,下面是执行方法
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

//阻塞队列，当一个线程尝试从队列中获取数据，如果队列为空，则阻塞等待，直到有数据为止
//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VoucherOrderHandler implements Runnable{
//
//        @Override
//        public void run() {
//            while(true){
//                try {
//                    //1.获取队列中的订单信息
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    //2.创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常",e);
//                }
//            }
//        }
//    }

    //Stream消息队列解决异步下单业务
    //线程任务，获取订单队列中的订单信息，进行下单获得优惠卷，要在用户秒杀抢购之前获得优惠卷
    //在这个类初始化，就要执行该任务，进行异步下单
    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while(true){
                try {
                    //1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        //2.1如果获取失败，说明没有消息，继续下一次循环,重复上面代码
                        continue;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认 SACK stream.orders g1 id
                    //record.getId() 消息id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while(true){
                try {
                    //1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息是否获取成功
                    if(list == null || list.isEmpty()){
                        //2.1如果获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }

        }
    }

    //异步下单，创建订单的业务逻辑
    private void handleVoucherOrder(VoucherOrder voucherOrder) throws InterruptedException {
        //1.获取用户,该方法是线程池中的线程执行的，不是主线程执行的，所以不能用UserHolder
        Long userId = voucherOrder.getUserId();
        //2.创建锁(可重入)的对象
        RLock lock = redissonClient.getLock(LOCK_ORDER_KEY + userId);

        //参数分别是：获取锁的最大等待时间（期间会重试），锁自动释放时间，时间单位
//        boolean isLock = lock.tryLock(1,10, TimeUnit.SECONDS);
        //3.获取锁
        boolean isLock = lock.tryLock(1L,TimeUnit.SECONDS);
        //4.判断是否获取锁成功
        if (!isLock) {
            //获取锁失败,返回错误或者重试
            log.error("不允许重复下单");
            return ;
        }
        try {
              //用代理对象调用该方法才有事务功能,还要引入aspectjweaver依赖,还要在application暴露该对象
              proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedisIdWorker redisIdWorker;

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠卷
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        //3.判断秒杀是否已经结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//
//
//        Long userId = UserHolder.getUser().getId();
//
////        synchronized (userId.toString().intern()) {
////            //获取事物代理对象
////            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
////            return  proxy.createVoucherOrder(voucherId);
////        }
//
//        //创建锁的对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//
//        //获取锁
//        boolean isLock = lock.tryLock();
//
//        if (!isLock) {
//            //获取锁失败,返回错误或者重试
//            return Result.fail("不允许重复下单");
//        }
//
//        try {
//            //获取事物代理对象
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return  proxy.createVoucherOrder(voucherId);
//        } finally {
//            //释放锁
//            lock.unlock();
//        }
//
//    }
    private IVoucherOrderService proxy; //代理对象

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户
//        Long userId = UserHolder.getUser().getId();
//        //1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                userId.toString()
//        );
//        //2.判断结果是否为0
//        int r = result.intValue();
//        if(result != 0){
//            //2.1 不为0 代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //2.2 为0，有购买资格，把下单信息保存到阻塞队列
//        //2.3创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //2.4订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //2.5用户id
//        voucherOrder.setUserId(userId);
//        //2.6代金卷id
//        voucherOrder.setVoucherId(voucherId);
//        //2.7放入阻塞队列
//        orderTasks.add(voucherOrder);
//        //获取事物代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//
//        //3.返回订单id
//        return Result.ok(orderId);
//    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        //订单id
        long orderId = redisIdWorker.nextId("order");
        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                //TODO 没有key
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        if(r != 0){
            //2.1 不为0 代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }


        //获取事物代理对象,提前获取异步下单，创建订单的代理对象,因为异步下单是子线程，而代理对象要在主线程获取
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(orderId);
    }

    //事务用的是该类的动态代理对象做的事务处理
    // 如果直接在该类调用该方法，事务无效，应该用代理对象调用该方法，事务才能生效
    @Transactional
    //事务的方法里面不能加锁，因为事物在释放锁后提交，这期间可能会有线程安全问题
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
//        Long userId = UserHolder.getUser().getId();
        Long userId = voucherOrder.getUserId();

        //5.1查询订单
        int count = query()
                .eq("user_id", userId)
                .eq("voucher_id", voucherOrder.getVoucherId())
                .count();
        //5.2判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次");
            return ;
        }

        //6.扣减库存 ，更新数据用乐观锁
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock -1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                //乐观锁避免超卖，本来应该eq("stock", voucher.getStock()) 才是线程安全，但会出现票卖不出去的问题
                .gt("stock", 0)
                .update();

        if (!success) {
            log.error("库存不足!");
            return ;
        }
        save(voucherOrder);
//        //7.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //7.1订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        voucherOrder.setUserId(userId);
//        //7.3代金卷id
//        voucherOrder.setVoucherId(voucherOrder);

        //8.返回订单id
//        return Result.ok(voucherOrder);
        }

}
